Cellular wakeup receiver for reducing power consumption of user equipment employing lte-wlan aggregation

ABSTRACT

A cellular wakeup receiver (C-WuRx) for reducing power consumption of a wireless wide area network (WWAN) radio of a user equipment (UE) includes receiver circuitry to receive a wakeup signal from a base station in response to the UE performing link aggregation by which downlink communications from the base station are offloaded to a wireless local area network (WLAN). The C-WuRx also includes processing circuitry to configure the receiver circuitry to periodically monitor at least a portion of a WWAN band for the wakeup signal and process the wakeup signal to cause the WWAN radio to resume receiving the downlink communications from the base station.

TECHNICAL FIELD

The field of the present disclosure relates generally to a low-power,low-latency Cellular Wake-Up Receiver (C-WuRx) and, more particularly,to a C-WuRx for reducing power consumption during Long Term Evolution(LTE) and Wireless Local Area Network (WLAN) aggregation (LTE-WLANaggregation, or LWA), which entails a User Equipment device (or simply,a UE) supporting LTE standards for accessing a Wireless Wide AreaNetwork (WWAN) and Wi-Fi standards for accessing a WLAN so as tosimultaneously employ both LTE and Wi-Fi links.

BACKGROUND INFORMATION

Wireless mobile communication technology uses various standards andprotocols to transmit data between a base station and a wireless mobiledevice. Wireless communication system standards and protocols caninclude those of the 3rd Generation Partnership Project (3GPP) relatingto LTE; the Institute of Electrical and Electronics Engineers (IEEE)relating to the 802.16 standards, which is commonly known to industrygroups as worldwide interoperability for microwave access (WiMAX); andthe IEEE relating to the 802.11 standard for WLAN, which is commonlyknown to industry groups as Wi-Fi®.

In Radio Access Networks (RANs) of LTE systems, the base station caninclude a RAN node such as a Evolved Universal Terrestrial Radio AccessNetwork (E-UTRAN) Node B (also commonly denoted as evolved Node B,enhanced Node B, eNodeB, or eNB) and Radio Network Controller (RNC) inan E-UTRAN, which communicate with a wireless communication device,i.e., a UE.

RANs use a Radio Access Technology (RAT) to communicate between the RANnode and UE through technologies including Global System for Mobilecommunications (GSM), Enhanced Data rates for GSM Evolution (EDGE) RAN(GERAN), Universal Terrestrial Radio Access Network (UTRAN), or E-UTRAN,which provide access to communication services through a core network.Thus, each of the RANs operates according to a specific 3GPP RAT.

A core network can be connected to the UE through the RAN node. The corenetwork can include a Serving Gateway (SGW), a Packet Data Network (PDN)Gateway (PGW), an Access Network Detection and Selection Function(ANDSF) server, an enhanced Packet Data Gateway (ePDG), or a MobilityManagement Entity (MME).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a pair of UEs connected to theInternet through WWAN and WLAN links.

FIG. 2 is a block diagram showing an example of cellular (i.e., LTE)network components.

FIG. 3 is a block diagram of a UE having a C-WuRx, which is alsoreferred to as a low-power wakeup radio (LP-WUR).

FIG. 4 is a sequence diagram of a connectivity procedure performed bythe UE of FIG. 3 when accessing the LTE network of FIG. 2.

FIG. 5 is a pair of flow charts showing processes, performed by the UEof FIG. 3 and an eNB of FIG. 2, for initiating and terminating alow-power mode in the UE.

FIG. 6 is a sequence diagram showing a process of the LTE network ofFIG. 2 waking the UE of FIG. 3 through its C-WuRx capabilities prior todelivering downlink data.

FIGS. 7A and 7B are charts of LTE subframes showing example locations ofLP-WUR wakeup signals in Physical Resource Blocks (PRBs) of the eachsubframe.

FIG. 8 is a pair of block diagrams of a UE and an eNB.

FIG. 9 is a block diagram illustrating components of a machine,according to some example embodiments, able to read instructions from amachine-readable medium and perform one or more of the methods discussedherein.

FIG. 10 is a series of three timing, power consumption, and radioconfiguration graphs showing conventional behavior of a UE in aConnected mode of Discontinuous Reception (C-DRX).

FIG. 11 is another series of three timing, power consumption, and radioconfiguration graphs showing how a C-WuRx reduces power consumptionwhile preserving a connection state of a main radio.

FIG. 12 is a sequence diagram showing example Radio Resource Control(RRC) message exchange for eNB-initiated WLAN offload and LTE linkpower-down.

DETAILED DESCRIPTION OF EMBODIMENTS

This section of the disclosure is organized into eight subsections.First, an overview of wakeup receiver technology is provided. Second,examples of operating environments and systems are set forth. Third, anexample UE including an LP-WUR is described. Fourth, techniques foremploying a wakeup receiver in cellular-based networks (e.g., LTE) aredescribed. Fifth, further examples of UEs and eNBs are provided. Sixth,example use cases for the wakeup receiver during LWA are described.Seventh, a summary of example embodiments is set forth. Eighth, andfinally, concluding remarks are provided.

I. Overview

Wakeup receivers are low-power radios optimized to receive a specificmessage or set of messages and, in response, change a state of a main,higher power radio modem (which is also referred to as simply a mainradio or a main modem) based on the message. Because wakeup receiversare optimized to receive specific messages, they can consume much lesspower than a main radio even when the main radio is in its lower poweridle state or other Power Saving Mode (PSM).

Conventional wakeup receivers have been implemented in some well-knowncontention-based protocols, i.e., so-called listen-before-talk operatingprocedures defined in IEEE 802.11 (Wi-Fi). In contrast, implementing awakeup receiver for cellular technologies is challenging because thesetechnologies are typically not a contention-based medium; they arescheduled mediums. In scheduled technologies such as LTE, a main radiomay use a random access preamble for non-contention-based random access,at which point the main radio regularly expects control channelinformation that schedules uplink and downlink data.

Previous attempts to reduce power consumption in a cellular radio—whilealso fulfilling a desire to have the radio reachable by the networkwithin a few hundred milliseconds—have entailed paging. But paging stilltends to waste power. For example, LTE networks (including LTE Advanced(LTE-A) networks under a March 2014 release 12 (Rel-12) of the 3GPPstandardization effort) expect a UE to be reachable in response topaging, which may entail the UE waking every fixed interval, e.g., every2.56 seconds (s) to check with the network on whether there is anydownlink data waiting for the UE. Many times, the paging mechanisminitiates a UE power up and power down simply for a check that indicatesno downlink data is available. In these instances, paging unnecessarilyconsumes power and is therefore not an effective power-saving solution.Furthermore, even when a main cellular modem is in an idle state, itstill consumes a relatively large amount of energy, particularly becausecellular radios are highly sensitive so as to receive signals inrelatively large cells (e.g., up to 1.5 kilometers in diameter) that aremuch larger than those of non-cellular wireless access technologies(e.g., up to a few hundred meters).

This disclosure describes a C-WuRx for a main cellular modem that, insome embodiments, facilitates a power savings on the order of 100× lesspower consumption. Accordingly, the description addresses techniques to(1) communicate whether devices are capable of sending or receiving awakeup signal conveyed within an LTE band, (2) convey such signalswithin the band, (3) establish what information is signaled, (4) augmentexiting paging mechanisms so as to support the wakeup signalfunctionality and allow UEs in an idle state to reactivate their radiosand thereby receive a paging message, and (5) address use cases for thewakeup receiver in the context of aggregation or WWAN and WLAN links.

Additional aspects and advantages will be apparent from the followingdescription of embodiments, which proceeds with reference to theaccompanying drawings that have identical reference numbers in multipledrawings to reference the same (or similar) features.

II. Examples of Operating Environments and Associated Systems

FIG. 1 illustrates an architecture of a wireless network with variouscomponents of the network, in accordance with some embodiments. A system100 is shown to include a UE 102 and a UE 104. The UEs 102 and 104 areillustrated as smartphones (i.e., handheld touchscreen mobile computingdevices connectable to one or more cellular networks), but can alsoinclude personal digital assistants (PDAs), pagers, laptop computers,desktop computers, and the like.

The UEs 102 and 104 are configured to access a RAN 106 via connections120 and 122, respectively, each of which comprise a physicalcommunications interface or layer; in this example, the connections 120and 122 are illustrated as an air interface to enable communicativecoupling, and can be consistent with cellular communications protocols,such as a GSM protocol, a Code-Division Multiple Access (CDMA) networkprotocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC)protocol, a Universal Mobile Telecommunications System (UMTS) protocol,a 3GPP LTE protocol, and the like.

In some embodiments described in further detail below, any of the UEs102 and 104 can comprise an Internet of Things (IoT) UE, which cancomprise a network access layer designed for low-power IoT applicationsutilizing short-lived UE connections.

An IoT UE can utilize technologies such as Machine-to-Machine (M2M) orMachine-Type Communications (MTC) for (machine initiated) exchangingdata with an MTC server and/or device via a Public Land Mobile Network(PLMN), Device-to-Device (D2D) communication, sensor networks, or IoTnetworks. An IoT network describes interconnecting uniquely identifiableembedded computing devices (within the Internet infrastructure) havingshort-lived connections, in addition to background applications (e.g.,keep-alive messages, status updates, etc.) executed by the IoT UE.

The RAN 106 can include one or more access points that enable theconnections 120 and 122. These access points (described in furtherdetail below) can be referred to as access nodes, base stations (BSs),NodeBs, eNBs, and so forth, and can comprise ground stations (i.e.,terrestrial access points) or satellite access points providing coveragewithin a geographic area (i.e., a cell). The RAN 106 is shown to becommunicatively coupled to a core network 110. The core network 110 canbe used to enable a packet-switched data exchange with the Internet 112in addition to bridging circuit switched calls between the UEs 102 and104. In some embodiments, the RAN 106 can comprise an E-UTRAN, and thecore network 110 can comprise an Evolved Packet Core (EPC) network.

The UE 104 is shown to be configured to access an access point (AP) 108via connection 124. The connection 124 can comprise a local wirelessconnection, such as a connection consistent with IEEE 802.11, whereinthe AP 108 would comprise a Wi-Fi router. In this example, the AP 108 isshown to be connected to the Internet 112 without connecting to the corenetwork 110.

The Internet 112 is shown to be communicatively coupled to anapplication server 116. The application server 116 can be implemented asa plurality of structurally separate servers or can be included in asingle server. The application server 116 is shown as connected to boththe Internet 112 and the core network 110; in other embodiments, thecore network 110 connects to the application server 116 via the Internet112. The application server 116 can also be configured to support one ormore communication services (e.g., Voice-over-Internet Protocol (VoIP)sessions, PTT sessions, group communication sessions, social networkingservices, etc.) for UEs that can connect to the application server 116via the core network 110 and/or the Internet 112.

The core network 110 is further shown to be communicatively coupled toInternet Protocol (IP) Multimedia Subsystem (IMS) 114. The IMS 114comprises an integrated network of telecommunications carriers that canenable the use of IP for packet communications, such as traditionaltelephony, fax, email, Internet access, VoIP, Instant Messaging (IM),videoconference sessions and Video on Demand (VoD), and the like.

FIG. 2 illustrates an architecture of components of a cellular network,in accordance with some embodiments. In this example, (sub)system 200comprises an Evolved Packet System (EPS) on an LTE network, and thusincludes an E-UTRAN 210 and an EPC network 220 communicatively coupledvia an S1 interface 215. In this illustration, only a portion of thecomponents of E-UTRAN 210 and the EPC network 220 are shown. Some of theelements described below may be referred to as “modules” or “logic.” Asreferred to herein, “modules” or “logic” may describe hardware (such asa circuit), software (such as a program driver), or a combinationthereof (such as a programmed micro-processing unit).

The E-UTRAN 210 includes eNBs 212 (which can operate as base stations)for communicating with one or more UEs (e.g., the UE 102). The eNBs 212are shown in this example to include macro eNBs and low-power (LP) eNBs.Any of the eNBs 212 can terminate the air interface protocol and can bethe first point of contact for the UE 102. In some embodiments, any ofthe eNBs 212 can fulfill various logical functions for the E-UTRAN 210including but not limited to radio network controller (RNC) functionssuch as radio bearer management, uplink and downlink dynamic radioresource management and data packet scheduling, and mobility management.The eNBs in EPS/LTE networks, such as the eNBs 212, do not utilize aseparate controller (i.e., an RNC) to communicate with the EPC network220; in other embodiments utilizing other specification protocols, RANscan include an RNC to enable communication between BSs and corenetworks.

In accordance with some embodiments, the UE 102 can be configured tocommunicate using Orthogonal Frequency-Division Multiplexing (OFDM)communication signals with any of the eNBs 212 over a multicarriercommunication channel in accordance various communication techniques,such as an Orthogonal Frequency-Division Multiple Access (OFDMA)communication technique or a Single Carrier Frequency Division MultipleAccess (SC-FDMA) communication technique, although the scope of theembodiments is not limited in this respect. The OFDM signals cancomprise a plurality of orthogonal subcarriers.

In accordance with some embodiments, the UE 102 can be configured todetermine a synchronization reference time based on reception of one ormore signals from any of the eNBs 212. The UE 102 can also be configuredto support D2D communication with other UEs using OFDMA, SC-FDMA, orother multiple access schemes.

The S1 interface 215 is the interface that separates the E-UTRAN 210 andthe EPC network 220. It is split into two parts: the S1-U, which carriestraffic data between the eNBs 212 and the SGW 224, and the S1-MME, whichis a signaling interface between the eNBs 212 and the MMEs 222. An X2interface is the interface between eNBs 212. The X2 interface cancomprise two parts (not shown): the X2-C and X2-U. The X2-C is thecontrol plane interface between the eNBs 212, while the X2-U is the userplane interface between the eNBs 212.

With cellular networks, low-power cells can be used to extend coverageto indoor areas where outdoor signals do not reach well, or to addnetwork capacity in areas with very dense phone usage, such as trainstations. As used herein, the term “LP eNB” refers to any suitablerelatively low-power eNB for implementing a smaller cell (i.e., smallerthan a macro cell) such as a femtocell, a picocell, or a microcell atthe edge of the network. Femtocell eNBs are typically provided by amobile network operator to its residential or enterprise customers. Afemtocell is typically the size of a residential gateway or smaller, andgenerally connects to the user's broadband line. Once plugged in, thefemtocell connects to the mobile operator's mobile network and providesextra coverage in a range of typically 30 to 50 meters for residentialfemtocells. Thus, an LP eNB might be a femtocell eNB since it is coupledthrough the packet data network gateway (PGW) 226. Similarly, a picocellis a wireless communication system typically covering a small area, suchas in-building (offices, shopping malls, train stations, etc.) or, morerecently, in-aircraft. A picocell eNB can generally connect through theX2 link to another eNB, such as a macro eNB, through its base stationcontroller (BSC) functionality. Thus, an LP eNB can be implemented witha picocell eNB since it is coupled to a macro eNB via an X2 interface.Picocell eNBs or other LP eNBs can incorporate some or all functionalityof a macro eNB. In some cases, this can be referred to as an AP BS orenterprise femtocell.

In some embodiments, a downlink resource grid can be used for downlinktransmissions from any of the eNBs 212 to the UE 102, while uplinktransmission from the UE 102 to any of the eNBs 212 can utilize similartechniques. The grid can be a time-frequency grid, called a resourcegrid or time-frequency resource grid, which is the physical resource inthe downlink in each slot. Such a time-frequency plane representation isa common practice for OFDM systems, which makes it intuitive for radioresource allocation. Each column and each row of the resource gridcorresponds to one OFDM symbol and one OFDM subcarrier, respectively.The duration of the resource grid in the time domain corresponds to oneslot in a radio frame. The smallest time-frequency unit in a resourcegrid is denoted as a resource element. Each resource grid comprises anumber of resource blocks, which describe the mapping of certainphysical channels to resource elements. Each resource block comprises acollection of resource elements; in the frequency domain, thisrepresents the smallest quantity of resources that currently can beallocated. There are several different physical downlink channels thatare conveyed using such resource blocks.

The Physical Downlink Shared Channel (PDSCH) carries user data andhigher-layer signaling to the UE 102. The Physical Downlink ControlChannel (PDCCH) carries information about the transport format andresource allocations related to the PDSCH channel, among other things.It also informs the UE 102 about the transport format, resourceallocation, and Hybrid Automatic Repeat Request (HARQ) informationrelated to the uplink shared channel. Typically, downlink scheduling(assigning control and shared channel resource blocks to the UE 102within a cell) is performed at any of the eNBs 212 based on channelquality information fed back from the UE 102 to any of the eNBs 212, andthen the downlink resource assignment information is sent to the UE 102on the PDCCH used for (assigned to) the UE.

The PDCCH uses Control Channel Elements (CCEs) to convey the controlinformation. Before being mapped to resource elements, the PDCCHcomplex-valued symbols are first organized into quadruplets, which arethen permuted using a sub-block inter-leaver for rate matching. EachPDCCH is transmitted using one or more of these CCEs, where each CCEcorresponds to nine sets of four physical resource elements known asResource Element Groups (REGs). Four Quadrature Phase Shift Keying(QPSK) symbols are mapped to each REG. The PDCCH can be transmittedusing one or more CCEs, depending on the size of the Downlink ControlInformation (DCI) and the channel condition. There can be four or moredifferent PDCCH formats defined in LTE with different numbers of CCEs(e.g., aggregation level, L=1, 2, 4, or 8).

The EPC network 220 includes the MMEs 222, the S-GW 224, and a PGW 226.The MMEs 222 are similar in function to the control plane of legacyServing General Packet Radio Service (GPRS) Support Nodes (SGSN). TheMMEs 222 manage mobility aspects in access such as gateway selection andtracking area list management. The S-GW 224 terminates the interfacetoward the E-UTRAN 210 and routes data packets between the E-UTRAN 210and the EPC network 220. In addition, the S-GW 224 can be a localmobility anchor point for inter-eNB handovers and can also provide ananchor for inter-3GPP mobility. Other responsibilities can includelawful intercept, charging, and some policy enforcement.

The S-GW 224 and the MMEs 222 can be implemented in one physical node orseparate physical nodes. The PGW 226 terminates an SGi interface towardthe PDN. The PGW 226 routes data packets between the EPC network 220 andexternal networks (e.g., the Internet), and can be a key node for policyenforcement and charging data collection. The PGW 226 and S-GW 224 canbe implemented in one physical node or separated physical nodes.

The UE 102 performs cell selection upon power-up and cell reselectionsthroughout its operation. The UE 102 searches for a cell provided byE-UTRAN 210 (e.g., a macro cell or a picocell). During the cellreselection process, the UE 102 can measure reference signal strengthfor each neighboring cell (e.g., Reference Signal ReceivedPower/Reference Signal Received Quality (RSRP/RSRQ)) and select a cellbased on this measurement (e.g., select a cell with the highest RSRPvalue). After the UE 102 selects a cell, it can verify the accessibilityof the cell by reading the Master Information Block (MIB). If the UE 102fails to read the MIB of the selected cell, it can discard the selectedcell and repeat the above process until a suitable cell is discovered.

An RRC state indicates whether an RRC layer of the UE 102 is logicallyconnected to an RRC layer of the E-UTRAN 210. After the UE 102 iscommunicatively coupled to a cell (e.g., the UE can listen to eNBbroadcast channels), its RRC state is RRC_IDLE. When the UE 102 has datapackets to transmit or receive, its RRC state becomes connected(RRC_CONNECTED). The UE 102, when in an RRC_IDLE state, can associateitself to different cells.

When a large number of wireless devices are present in a network, theremay be scenarios where an end device does not have direct connectivityto an eNB(s) 212. For example, connectivity resources may be limited ordevices may comprise coverage-constrained devices (e.g., devicesoperating primarily for MTC or M2M communications (e.g., sensor devices,controller devices, etc.) may have limited coverage and processingcapabilities (similarly, devices may operate in a coverage constrainedmode to limit power/resource consumption)). The connectivity for such adevice may be provided using a multi-hop transmission path foruplink/downlink paths to/from the eNB(s) 212. In other examples, amulti-hop transmission path may be more power efficient or have less ofa network traffic load compared to a direct UE-eNB path, and thus themulti-hop transmission path is utilized.

III. Example UE Including C-WuRx

Embodiments described herein may be implemented into a system using anysuitably configured hardware and/or software. FIG. 3 is a block diagramillustrating, for one embodiment, example components of a UE or mobilestation (MS) device 300. In some embodiments, mobile devices or otherdevices described herein can be part of a portable wirelesscommunication device, such as a PDA, a laptop or portable computer withwireless communication capability, a web tablet, a wireless telephone, asmartphone, a wireless headset, a pager, a wearable mobile computingdevice (e.g., a mobile computing device included in a wearable housing),an instant messaging device, a digital camera, an access point, atelevision, a medical device (e.g., a heart rate monitor, a bloodpressure monitor, etc.), or other device that can receive and/ortransmit information wirelessly. In some embodiments, the mobile deviceor other device can include one or more of a keyboard, a display, anon-volatile memory port, multiple antennas, a graphics processor, anapplication processor, speakers, and other mobile device elements. Thedisplay can be a liquid crystal display (LCD) screen including a touchscreen.

In some embodiments, the UE device 300 may include application circuitry302, baseband circuitry 304, Radio Frequency (RF) circuitry 306,front-end module (FEM) circuitry 308 for WWAN, a C-WuRx 350, FEMcircuitry 360 for WLAN, and one or more associated antennas 310, coupledtogether at least as shown. In some embodiments, the UE device 300 mayinclude additional elements such as, for example, memory/storage,display, camera, sensor, and/or input/output (I/O) interface.

The application circuitry 302 may include one or more applicationprocessors. For example, the application circuitry 302 may includecircuity such as one or more single-core or multi-core processors. Theprocessor(s) may include any combination of general-purpose processorsand dedicated processors (e.g., graphics processors, applicationprocessors, etc.). The processor(s) may be operably coupled and/orinclude memory/storage, and may be configured to execute instructionsstored in the memory/storage to enable various applications and/oroperating systems to run on the system.

The baseband circuitry 304 may include one or more single-core ormulti-core processors. The baseband circuitry 304 may include one ormore baseband processors and/or control logic. The baseband circuitry304 may be configured to process baseband signals received from areceive signal path of the RF circuitry 306. The baseband circuitry 304may also be configured to generate baseband signals for a transmitsignal path of the RF circuitry 306. The baseband processing circuitry304 may interface with the application circuitry 302 for generation andprocessing of the baseband signals, and for controlling operations ofthe RF circuitry 306. For example, in some embodiments, the basebandcircuitry 304 may include at least one of a second generation (2G)baseband processor 304A, a third generation (3G) baseband processor304B, a fourth generation (4G) baseband processor 304C, other basebandprocessor(s) 304D for other existing generations, and generations indevelopment or to be developed in the future (e.g., fifth generation(5G), 6G, etc.). The baseband circuitry 304 (e.g., at least one ofbaseband processors 304A-304D) may handle various radio controlfunctions that enable communication with one or more radio networks viathe RF circuitry 306. The radio control functions may include signalmodulation/demodulation, encoding/decoding, radio frequency shifting,other functions, and combinations thereof. In some embodiments,modulation/demodulation circuitry of the baseband circuitry 304 may beprogrammed to perform Fast-Fourier Transform (FFT), precoding,constellation mapping/demapping functions, other functions, andcombinations thereof. In some embodiments, encoding/decoding circuitryof the baseband circuitry 304 may be programmed to perform convolutions,tail-biting convolutions, turbo, Viterbi, Low Density Parity Check(LDPC) encoder/decoder functions, other functions, and combinationsthereof. Embodiments of modulation/demodulation and encoder/decoderfunctions are not limited to these examples, and may include othersuitable functions.

In some embodiments, the baseband circuitry 304 may include elements ofa protocol stack such as, for example, elements of an E-UTRAN protocolincluding, for example, Physical (PHY), Media Access Control (MAC),Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP),and/or RRC elements. A Central Processing Unit (CPU) 304E of thebaseband circuitry 304 may be programmed to run elements of the protocolstack for signaling of the PHY, MAC, RLC, PDCP, and/or RRC layers. Insome embodiments, the baseband circuitry 304 may include one or moreaudio Digital Signal Processor(s) (DSP) 304F. The audio DSP(s) 304F mayinclude elements for compression/decompression and echo cancellation.The audio DSP(s) 304F may also include other suitable processingelements.

The baseband circuitry 304 may further include memory/storage 304G. Thememory/storage 304G may include data and/or instructions for operationsperformed by the processors of the baseband circuitry 304 storedthereon. In some embodiments, the memory/storage 304G may include anycombination of suitable volatile memory and/or non-volatile memory. Thememory/storage 304G may also include any combination of various levelsof memory/storage including, but not limited to, read-only memory (ROM)having embedded software instructions (e.g., firmware), random accessmemory (e.g., Dynamic Random Access Memory (DRAM)), cache, buffers, etc.In some embodiments, the memory/storage 304G may be shared among thevarious processors or dedicated to particular processors.

Components of the baseband circuitry 304 may be suitably combined in asingle chip, a single chipset, or disposed on a same circuit board insome embodiments. In some embodiments, some or all of the constituentcomponents of the baseband circuitry 304 and the application circuitry302 may be implemented together, such as, for example, on a System On aChip (SOC).

In some embodiments, the baseband circuitry 304 may provide forcommunication compatible with one or more radio technologies. Forexample, in some embodiments, the baseband circuitry 304 may supportcommunication with an E-UTRAN and/or other Wireless Metropolitan AreaNetworks (WMAN), a WLAN, a Wireless Personal Area Network (WPAN).Embodiments in which the baseband circuitry 304 is configured to supportradio communications of more than one wireless protocol may be referredto as multi-mode baseband circuitry.

The RF circuitry 306 may enable communication with wireless networksusing modulated electromagnetic radiation through a non-solid medium. Invarious embodiments, the RF circuitry 306 may include switches, filters,amplifiers, etc. to facilitate the communication with the wirelessnetwork. The RF circuitry 306 may include a receive signal path whichmay include circuitry to down-convert RF signals received from the FEMcircuitry 308, and provide baseband signals to the baseband circuitry304. The RF circuitry 306 may also include a transmit signal path whichmay include circuitry to up-convert baseband signals provided by thebaseband circuitry 304, and provide RF output signals to the FEMcircuitry 308 for transmission.

In some embodiments, the RF circuitry 306 may include a receive signalpath and a transmit signal path. The receive signal path of the RFcircuitry 306 may include mixer circuitry 306A, amplifier circuitry306B, and filter circuitry 306C. The transmit signal path of the RFcircuitry 306 may include filter circuitry 306C and mixer circuitry306A. The RF circuitry 306 may further include synthesizer circuitry306D configured to synthesize a frequency for use by the mixer circuitry306A of the receive signal path and the transmit signal path. In someembodiments, the mixer circuitry 306A of the receive signal path may beconfigured to down-convert RF signals received from the FEM circuitry308 based on the synthesized frequency provided by synthesizer circuitry306D. The amplifier circuitry 306B may be configured to amplify thedown-converted signals.

The filter circuitry 306C may include a Low-Pass Filter (LPF) orBand-Pass Filter (BPF) configured to remove unwanted signals from thedown-converted signals to generate output baseband signals. Outputbaseband signals may be provided to the baseband circuitry 304 forfurther processing. In some embodiments, the output baseband signals mayinclude zero-frequency baseband signals, although this is not arequirement. In some embodiments, the mixer circuitry 306A of thereceive signal path may comprise passive mixers, although the scope ofthe embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 306A of the transmit signalpath may be configured to up-convert input baseband signals based on thesynthesized frequency provided by the synthesizer circuitry 306D togenerate RF output signals for the FEM circuitry 308. The basebandsignals may be provided by the baseband circuitry 304 and may befiltered by filter circuitry 306C. The filter circuitry 306C may includea LPF, although the scope of the embodiments is not limited in thisrespect. In some embodiments, the mixer circuitry 306A of the receivesignal path and the mixer circuitry 306A of the transmit signal path mayinclude two or more mixers, and may be arranged for quadraturedownconversion and/or upconversion, respectively. In some embodiments,the mixer circuitry 306A of the receive signal path and the mixercircuitry 306A of the transmit signal path may include two or moremixers and may be arranged for image rejection (e.g., Hartley imagerejection). In some embodiments, the mixer circuitry 306A of the receivesignal path and the mixer circuitry 306A may be arranged for directdownconversion and/or direct upconversion, respectively. In someembodiments, the mixer circuitry 306A of the receive signal path and themixer circuitry 306A of the transmit signal path may be configured forsuper-heterodyne operation.

In some embodiments, the output baseband signals and the input basebandsignals may be analog baseband signals, although the scope of theembodiments is not limited in this respect. In some alternateembodiments, the output baseband signals and the input baseband signalsmay be digital baseband signals. In such embodiments, the RF circuitry306 may include Analog-to-Digital Converter (ADC) and Digital-to-AnalogConverter (DAC) circuitry, and the baseband circuitry 304 may include adigital baseband interface to communicate with the RF circuitry 306.

In some dual-mode embodiments, separate radio integrated circuit (IC)circuitry may be provided for processing signals for each spectrum,although the scope of the embodiments is not limited in this respect.

In some embodiments, the synthesizer circuitry 306D may include one ormore of a fractional-N synthesizer and a fractional N/N+1 synthesizer,although the scope of the embodiments is not limited in this respect asother types of frequency synthesizers may be suitable. For example,synthesizer circuitry 306D may include a delta-sigma synthesizer, afrequency multiplier, a synthesizer comprising a phase-locked loop witha frequency divider, other synthesizers and combinations thereof.

The synthesizer circuitry 306D may be configured to synthesize an outputfrequency for use by the mixer circuitry 306A of the RF circuitry 306based on a frequency input and a divider control input. In someembodiments, the synthesizer circuitry 306D may be a fractional N/N+1synthesizer.

In some embodiments, frequency input may be provided by a VoltageControlled Oscillator (VCO), although that is not a requirement. Dividercontrol input may be provided by either the baseband circuitry 304 orthe applications processor 302 depending on the desired outputfrequency. In some embodiments, a divider control input (e.g., N) may bedetermined from a look-up table based on a channel indicated by theapplications processor 302.

The synthesizer circuitry 306D of the RF circuitry 306 may include adivider, a Delay-Locked Loop (DLL), a multiplexer and a phaseaccumulator. In some embodiments, the divider may include a Dual ModulusDivider (DMD), and the phase accumulator may include a Digital PhaseAccumulator (DPA). In some embodiments, the DMD may be configured todivide the input signal by either N or N+1 (e.g., based on a carry out)to provide a fractional division ratio. In some example embodiments, theDLL may include a set of cascaded, tunable, delay elements, a phasedetector, a charge pump and a D-type flip-flop. In such embodiments, thedelay elements may be configured to break a VCO period up into Nd equalpackets of phase, where Nd is the number of delay elements in the delayline. In this way, the DLL may provide negative feedback to help ensurethat the total delay through the delay line is one VCO cycle.

In some embodiments, the synthesizer circuitry 306D may be configured togenerate a carrier frequency as the output frequency. In someembodiments, the output frequency may be a multiple of the carrierfrequency (e.g., twice the carrier frequency, four times the carrierfrequency, etc.) and used in conjunction with a quadrature generator anddivider circuitry to generate multiple signals at the carrier frequencywith multiple different phases with respect to each other. In someembodiments, the output frequency may be a LO frequency (fLO). In someembodiments, the RF circuitry 306 may include an IQ/polar converter.

The FEM circuitry 308 may include a receive signal path which mayinclude circuitry configured to operate on RF signals received from oneor more antennas 310, amplify the received signals, and provide theamplified versions of the received signals to the RF circuitry 306 forfurther processing. The FEM circuitry 308 may also include a transmitsignal path which may include circuitry configured to amplify signalsfor transmission provided by the RF circuitry 306 for transmission by atleast one of the one or more antennas 310.

In some embodiments, the FEM circuitry 308 may include a TX/RX switchconfigured to switch between a transmit mode and a receive modeoperation. The FEM circuitry 308 may include a receive signal path and atransmit signal path. The receive signal path of the FEM circuitry 308may include a Low-Noise Amplifier (LNA) to amplify received RF signalsand provide the amplified received RF signals as an output (e.g., to theRF circuitry 306). The transmit signal path of the FEM circuitry 308 mayinclude a Power Amplifier (PA) configured to amplify input RF signals(e.g., provided by RF circuitry 306), and one or more filters configuredto generate RF signals for subsequent transmission (e.g., by one or moreof the one or more antennas 310.

In some embodiments, the MS device 300 may include additional elementssuch as, for example, memory/storage, a display, a camera, one or moresensors, an Input/Output (I/O) interface, other elements, andcombinations thereof.

In some embodiments, the MS device 300 may be configured to perform oneor more processes, techniques, and/or methods as described herein, orportions thereof.

In some embodiments, the UE 300 comprises a plurality of power savingmechanisms. If the UE 300 is in an RRC_CONNECTED state, where it isstill connected to the eNB because it expects to receive trafficshortly, then it may enter a state known as DRX mode after a period ofinactivity. During this state, the device may power down for briefintervals of time and thus save power.

If there is no data traffic activity for an extended period of time,then the UE 300 may transition off to an RRC_IDLE state, where itdisconnects from the network and does not perform operations such aschannel quality feedback, handover, and the like. The UE 300 goes into avery low power state and it performs paging where it periodically wakesup to listen to the network and then powers down again. The devicecannot receive data in this state; in order to receive data, ittransitions back to RRC_CONNECTED state.

An additional power saving mode may allow a device to be unavailable tothe network for periods longer than a paging interval (ranging fromseconds to a few hours). During this time, the device is totallyunreachable to the network and may power down completely. Any data sentduring this time incurs a large delay and it is assumed the delay isacceptable.

As discussed above, the UE device 300 may comprise a network accesslayer designed for low-power applications utilizing short-lived UEconnections, such as a low-power IoT UE (e.g., an MTC or M2M device).IoT UEs may be utilized in applications having a potentially highlatency in downlink transmissions (i.e., the device may power downcompletely for large periods of time to save power and may beunavailable to the network).

In this embodiment, the C-WuRx 350 is a low-power radio separate fromthe FEM circuitry 308. The C-WuRx 350 may remain awake continuously (orat high-frequency intervals) and monitor for a wakeup signal, allowingthe FEM circuitry 308 to remain powered down in the absence of downlinkdata. When the C-WuRx 350 detects the wakeup signal, the C-WuRx 350 maybe configured to wake up the FEM circuitry 308 to receive incomingdownlink data.

In some embodiments, a simple radio waveform (e.g., a narrow-band wakeupsignal comprising an On-Off Key (OOK) modulated tone) may be used tosignal pending downlink data for the UE 300, rather than a highlycomplex OFDM having the precise synchronization characteristics of astandard LTE channel. This simple waveform allows for the C-WuRx 350 toremain awake and still consume less power than the FEM circuitry 308,thereby significantly increasing the battery life of the UE 300. Sinceits waveform may be different from that of LTE, processing circuitry ofthe C-WuRx may also be different and provide for reduced powerconsumption.

IV. Wakeup Receiver Signaling and Functionality

FIG. 4 is a flow diagram of a connectivity procedure for a UE inaccordance with some embodiments. Process and logical flow diagrams asillustrated herein provide examples of sequences of various processactions. Although shown in a particular sequence or order, unlessotherwise specified, the order of the actions can be modified. Thus, thedescribed and illustrated implementations should be understood only asexamples, and the illustrated processes can be performed in a differentorder, and some actions can be performed in parallel. Additionally, oneor more actions can be omitted in various embodiments; thus, not allactions are executed in every implementation. Other process flows arepossible.

In this embodiment, an RRC signaling mechanism is used to exchangeLP-WUR capability information of the UE 300 with other components of anLTE network. A process 400 is illustrated as an attachment messagingsequence, and is shown to include several messages exchanged betweennetwork components for establishing an RRC connection; in someembodiments, other messages may be exchanged in addition to the messagesdescribed below.

The UE 300 sends an RRC Connection Request message 401 to the eNB 212.The eNB 212 sends an RRC Connection Setup message 402 to the UE 300;this message 402 includes configuration information for a Signal RadioBearer (SRB).

The UE 300 sends an RRC Connection Setup Complete message 403, whichincludes a Non-Access Stratum (NAS) service request for attaching to anEPC, to the eNB 212. The message 403 can include data indicating the UE300 has LP-WUR capability (i.e., the UE 300 includes the C-WuRx 350).

The eNB 212 forwards the service request message (shown as a message404, which also includes the data indicating that the UE 300 includesthe C-WuRx 350) to a network control entity of an EPC (in this example,the MME 222). In some embodiments, if rejection of the connectionrequest is taken care of by another message, uplink (UL) grant cansimply be sent in the PDCCH and message 404 is not sent.

The MME 222 sends an initial context setup request message 405 to theeNB 212. The message 405 can includes information from an authenticationsecurity routine. The eNB 212 sends an RRC Connection Reconfigurationmessage 406, which includes configuration information for one or moredata radio bearers (DRBs), to the UE 300. The UE 300 sends an RRCConnection Reconfiguration Complete message 407 to the eNB 212 toestablish one or more DRBs.

Thus, the MME 222 and the eNB 212 are aware that the UE 300 has LP-WURcapabilities, and may be reached through LP-WUR signals when the FEMcircuitry 308 of the UE 300 is in an RRC_IDLE state. Other embodimentsmay signal this information to components of the network (e.g., viaFeature Group Indicator (FGI) bits in the UE Capability Informationresponse).

FIG. 5 illustrates a process for initiating and terminating the UElow-power mode in accordance with some embodiments. A process 500 isshown to be executed via the UE 300 comprising the C-WuRx 350, and aprocess 520 is shown to be executed via the eNB 212. The process 500includes an operation for the UE 300 to execute a low-power mode (shownas block 502). As discussed above, if there is no data traffic activityfor an extended period of time, then the UE 300 may transition off to anRRC_IDLE state, where it disconnects from the network and does notperform operations such as channel quality feedback, handover, and thelike. The UE 300 goes into a very low power state wherein transceivercircuitry such as the FEM circuitry 308 is powered off.

For UEs utilized in an IoT/MTC application, high latency (e.g., everyfew minutes to hours) in uplink/downlink transmissions may be expected(i.e., the device may power down completely for large periods of time tosave power and may be unavailable to the network). The process 500includes an operation for the C-WuRx 350 to monitor (either continuouslyor at an interval to ensure a minimum latency threshold) for an LP-WURsignal from the eNB 212 (shown as block 504).

The process 520 includes an operation for the eNB 212 to receive anindication from the EPC that downlink data is present for the UE 300(shown as block 522). Because the eNB 212 is aware that the UE 300includes the C-WuRx 350, the eNB 212 executes an operation to transmit alow-power wakeup radio signal to the UE 300 (shown as block 524) ratherthan executing a legacy paging process. The eNB 212 subsequentlytransmits said downlink data (shown as block 526) (e.g., after apredetermined time period, after receiving an indication from the UE 300that its receiver circuitry is powered on, etc.).

As discussed above, the low-power wake up radio signal transmitted fromthe eNB 212 may comprise a non-OFDM signal with an extremely simplemodulation scheme such as OOK. In some embodiments, the low-power wakeup radio signal may include an identifying preamble pattern long enoughto ensure that it can be recognized as a LP-WUR signal by the C-WuRx 350of the UE 300. In some embodiments, the low-power wake up radio signalmay include a UE Identifier, such as a System Architecture Evolution(SAE)-Temporary Mobile Subscriber Identity (S-TMSI), which may be usedto uniquely identify the UE. In some embodiments, the low-power wake upradio signal may be transmitted so that it does not interfere with thereception of Primary and Secondary Synchronization Signals sent by theeNB to the UEs, pilot signals, or any of the control information. Insome embodiments, the low-power wake up radio signal may carry someinformation to the UE 300 to assist in the fast network entry (e.g.preamble for non-contention based random access).

The process 500 includes an operation for the UE 300 to receive anindication of either uplink data or downlink data (i.e., via thelow-power wakeup radio signal) (shown as block 506). The transceivercircuitry (e.g., the FEM circuitry 308 of the UE 300) is subsequentlypowered on (shown as block 508) and the uplink/downlink data issubsequently transmitted/received (shown as block 510).

FIG. 6 is a flow diagram for a process to send downlink data to a UEhaving LP-WUR capabilities in accordance with some embodiments. Aprocess 600 is executed while the UE 300 is executing an RRC_IDLE state610. During this state, there is no active connection between the eNB212 and the UE 300, and thus, the eNB 212 does not have information thatthe UE 300 is within its cell range.

The process 600 includes an operation for the S-GW 224 to transmit adownlink data notification to the MME 222 (shown as operation 601). TheMME 222 determines where the UE 300 may currently located (i.e., itstracking area (TA)) and pages all eNBs that the UE 300 (UE (identified,for example, via its IMSI or S-TMSI) has downlink data (shown asoperation 602); in this embodiment, the eNB 212 receives this pagingnotification because the UE 300 is within its cell range.

For UEs without LP-WUR capabilities, the MME 222 may send an S1-APpaging message (via, for example, the S1 interface 215 of FIG. 2) to eNB212 in order initiate a UE legacy wakeup process. In this embodiment,however, the MME 222 sends a paging notification including dataindicating the UE 300 has LP-WUR capabilities. The eNB 212 subsequentlysends a LP-WUR wakeup signal (shown as operation 603) rather than alegacy paging message to initiate any of the UE wakeup processesdiscussed above.

FIG. 7A and FIG. 7B are illustrations of LP-WUR wakeup signalconfigurations in accordance with some embodiments. A downlink signalconfiguration 700 is illustrated in FIG. 7A, including PrimarySynchronization Channel (P-SCH) and Secondary Synchronization Channel(S-SCH) signals. The downlink signal configuration 700 includes PRBsallocated for a Physical Control Format Indicator Channel (PCFICH), aPhysical HARQ Indication channel (PHICH), a PDSCH and a PDCCH. Otherdownlink channel signals may be included in other embodiments (e.g.,Physical Broadcast Channel (PBCH) signal data).

In this embodiment, a LP-WUR wake up signal configuration 710 is shownas using a limited amount of PRBs in a fixed location of the primaryband. As shown in this embodiment, the LP-WUR wake up signalconfiguration 710 comprises n PRBs×m subframes, which may be transmittedevery X minutes (dependent on the expected latency of the UE; asdiscussed above, IoT UEs may have a high expected latency).

Other LP-WUR wake up signal configurations may be used in otherembodiments. For example, a downlink signal configuration 750 isillustrated in FIG. 7B as including a LP-WUR wake up signalconfiguration 760 that uses a narrow frequency channel. In this example,the LP-WUR wake up signal configuration 760 comprises a low number ofPRBs (in this example, 6 PRBs)×m subframes, which may be transmittedevery X minutes if no response from the UE is received (dependent on theexpected latency of the UE). Other examples not illustrated includeLP-WUR wake up signal configurations included in a pre-determinedOut-Of-Band (OOB) or in the guard bands of primary or secondary bands.These example configurations allow for an extremely simple, yet uniquelyidentifiable LP-WUR wakeup radio signal such that the power costs ofreceiving and decoding it correctly over mobile broadband may beextremely low.

V. Additional Details on Devices

FIG. 8 shows a block diagram of a UE 800 and an eNB 850, in accordancewith some embodiments. It should be noted that in some embodiments, theeNB 850 can be a stationary (non-mobile) device. The UE 800 can includePHY 802 for transmitting and receiving signals to and from the eNB 850,other eNBs, other UEs, or other devices using one or more antennas 801,while the eNB 850 can include PHY 852 for transmitting and receivingsignals to and from the UE 800, other eNBs, other UEs, or other devicesusing one or more antennas 851. The UE 800 can also include MACcircuitry 804 for controlling access to the wireless medium, while theeNB 850 can also include MAC circuitry 854 for controlling access to thewireless medium. The UE 800 can also include processing circuitry 806and memory 808 arranged to perform the operations described herein, andthe eNB 850 can also include processing circuitry 856 and memory 858arranged to perform the operations described herein.

The antennas 801, 851 can comprise one or more directional oromnidirectional antennas, including, for example, dipole antennas,monopole antennas, patch antennas, loop antennas, microstrip antennas orother types of antennas suitable for transmission of RF signals. In someMultiple-Input Multiple-Output (MIMO) embodiments, the antennas 801, 851can be effectively separated to benefit from spatial diversity and thedifferent channel characteristics that can result.

Although the UE 800 and eNB 850 are each illustrated as having severalseparate functional elements, one or more of the functional elements canbe combined and can be implemented by combinations ofsoftware-configured elements, such as processing elements includingDSPs, and/or other hardware elements. For example, some elements cancomprise one or more microprocessors, DSPs, Field-Programmable GateArrays (FPGAs), Application Specific Integrated Circuits (ASICs), RF ICs(RFICs), and combinations of various hardware and circuitry forperforming at least the functions described herein. In some embodiments,the functional elements can refer to one or more processes operating onone or more processing elements.

Embodiments can be implemented in one or a combination of hardware,firmware, and software. Embodiments can also be implemented asinstructions stored on a computer-readable storage device, which can beread and executed by at least one processor to perform the operationsdescribed herein. A computer-readable storage device can include anynon-transitory mechanism for storing information in a form readable by amachine (e.g., a computer). For example, a computer-readable storagedevice can include read-only memory (ROM), random-access memory (RAM),magnetic disk storage media, optical storage media, flash-memorydevices, and other storage devices and media. Some embodiments caninclude one or more processors and can be configured with instructionsstored on a computer-readable storage device. FIG. 9, for example, is ablock diagram illustrating components, according to some exampleembodiments, able to read instructions from a machine-readable orcomputer-readable medium (e.g., a machine-readable storage medium) andperform any one or more of the methodologies discussed herein. In someembodiments, the components may be included in a UE or an eNB configuredto operate in accordance with 3GPP standards (e.g., LTE-A standard). Insome embodiments, the mobile device or other device can be configured tooperate according to other protocols or standards, including IEEE 802.11or other IEEE and 3GPP standards.

Specifically, FIG. 9 shows a diagrammatic representation of hardwareresources 900 including one or more processors (or processor cores) 910,one or more memory/storage devices 920, and one or more communicationresources 930, each of which are communicatively coupled via a bus 940.

The processors 910 (e.g., a CPU, a Reduced Instruction Set Computing(RISC) processor, a Complex Instruction Set Computing (CISC) processor,a Graphics Processing Unit (GPU), a DSP such as a baseband processor, anASIC, an RFIC, another processor, or any suitable combination thereof)may include, for example, a processor 912 and a processor 914. Thememory/storage devices 920 may include main memory, disk storage, or anysuitable combination thereof.

The communication resources 930 may include interconnection and/ornetwork interface components or other suitable devices to communicatewith one or more peripheral devices 904 and/or one or more databases 906via a network 908. For example, the communication resources 930 mayinclude wired communication components (e.g., for coupling via aUniversal Serial Bus (USB)), cellular communication components, NearField Communication (NFC) components, Bluetooth® components (e.g.,Bluetooth® Low Energy), Wi-Fi components, and other communicationcomponents.

Instructions 950 may comprise software, a program, an application, anapplet, an app, or other executable code for causing at least any of theprocessors 910 to perform any one or more of the methodologies discussedherein. The instructions 950 may reside, completely or partially, withinat least one of the processors 910 (e.g., within the processor's cachememory), the memory/storage devices 920, or any suitable combinationthereof. Furthermore, any portion of the instructions 950 may betransferred to the hardware resources 900 from any combination of theperipheral devices 904 and/or the databases 906. Accordingly, the memoryof processors 910, the memory/storage devices 920, the peripheraldevices 904, and the databases 906 are examples of computer-readable andmachine-readable media.

VI. C-WuRx for Reduced Power Consumption During Mobile Data Offloading

Offloading mobile data to unlicensed spectrum, also known as mobile dataoffloading or Wi-Fi offloading, includes techniques such as LWA and LTEWLAN radio level integration with IP security tunnel (LWIP).Enhancements to these techniques are being actively pursued bystandardization bodies of the 3GPP so as to leverage both the high datarates afforded by Wi-Fi and the reliable connectivity afforded by LTE.In the 13th release (Rel-13) of the 3GPP standards, work was completedon changes in protocol specifications that enabled offloading downlink(DL) data over WLAN using LWA. And in an upcoming Rel-14, a goal is tocomplete changes in protocol specifications that would also enableoffloading UL data over WLAN.

Many mobile data offloading techniques, e.g., LWA, LWIP, and the like,attempt to improve throughput performance by exploiting a UE's dualconnectivity while maintaining both Wi-Fi and LTE radios in activestates, thus increasing the power consumption substantially. LWA andLWIP architectures and protocols, for example, are designed such thatthere is an expectation of an active bearer between the UE and an eNB.The reason an active bearer is expected is because, currently, downlinkand uplink control messages (including information regarding WLANchannel quality measurements) are communicated via the LTE link. Thus, arelatively high power-consuming LTE modem in the UE is maintained in theRRC_CONNECTED state for the duration of the mobile data offloadingsession, even though the mobile data is being transmitted over the WLANlink using a lower-power WLAN modem.

Another approach for communicating control messages during mobile dataoffloading is for the UE to send and receive the messages over the WLANlink, which would facilitate offloading UL data over the WLAN andprovide an opportunity to enter the RRC_IDLE state. Even under thisapproach, however, there are still at least two reasons to maintain theUE in the RRC_CONNECTED state. First, maintaining the RRC_CONNECTEDstate reduces the latency of switching from Wi-Fi offloading back to LTEtransmissions. Second, it is challenging to reliably predict occasionsin which the WLAN link becomes congested or lacks sufficient coverage,whereas an LTE link provides a reliable connectivity option that enablessession continuity in response to a compromised WLAN link, thusimproving user experience.

Nevertheless, as noted previously, maintaining the RRC_CONNECTED statehas inhibited the UE from entering lower power states, even when itsdata exchanges occur over the WLAN link. Furthermore, while in theRRC_CONNECTED state, the UE may enter DRX state, but it will stillconsume more energy than it would have otherwise consumed in(non-offloading) lower-power idle states.

Disclosed are techniques that enable a UE to retain low latency accessto the WWAN, but at a lower power consumption state—lower than even thatof an RRC_IDLE state—while exchanging data over a WLAN link and whileallowing the UE to switch at a low latency back to using its WWAN link.Embodiments of a low-power C-WuRx provide a low-latency, low-powersolution for the UE to switch from WLAN to WWAN when desired.

More specifically, when the eNB offloads both UL and DL data exchange tothe WLAN link, rather than letting the LTE link be in a C-DRX energysaving state (based on inactivity timer settings), the LTE radio iscompletely shut down and a very low-power, low-latency C-WuRx is insteadused to manage the state of the LTE link in response to a narrow-bandwakeup signal. In other words, the C-WuRx is used to wake up the mainmodem when the eNB decides that switching from WLAN link utilization toLTE link utilization is desirable. And when the UE seeks to transmitcontrol traffic over the UL, then the UE may simply activate the LTEmodem and send the traffic as if it were normally transitioning out itslow-power mode of a conventional C-DRX implementation.

There are various reasons for why the UE may seek to send controlmessages. For example, the UE may want to ensure that its LTE connectionis not prematurely disconnected after the connection has been inactiveon the LTE channel for too long. In LTE systems, the eNB maintains aninactivity timer that transitions the UE from an RRC_CONNECTED state toan RRC_IDLE state if the eNB does not receive anything from the UE (i.e.data requests) for a predetermined period of time. Accordingly, in someembodiments the eNB may also suspend this inactivity timer during theC-WuRx active state since this timer value is typically in the range of10-12 seconds whereas the offloading to the WLAN may last longer thanthat.

LTE system convey control information through various means. Forexample, both UL and DL control information may be sent using RRCcontrol messages. Typically, UL control information from the UE iscurrently sent through LTE links. But in some embodiments when there isno data being transferred over LTE, then no LTE control informationwould be exchanged over LTE. Accordingly, control information may besent either over the WLAN, or the UE will wake up the LTE radio to sendit.

FIG. 10 shows example diagrams 1000 of timing 1010, power consumption1020, and main radio configurations 1030 of a UE performing C-DRX whilein the RRC_CONNECTED state. The LTE radio powers down in low-power(sleep) states, but since the UE preserves all of the RRC stateinformation, as well as maintains timing synchronization with the LTEnetwork, the power consumption in the low-power states is still fairlyhigh, e.g., around 10 milliwatts (mW). And when the UE activates itsmain radio for the active duration period of C-DRX, which is typicallyin the order of 10 milliseconds (ms) plus additional time for thehardware to power up, the main radio consumes a relatively high amountof power (e.g., about 500 mW) so as to monitor the PDCCH in eachsub-frame. Note, however, that these power consumption numbers arerather optimistic, based on ideal conditions and optimized versions of atypical LTE modem. In actual practice, power consumption in the low- andhigh-power states is closer to, respectively, about 40 mW and about 600mW.

FIG. 10 also shows that, to further reduce power consumption duringC-DRX, the period of the DRX duty cycle may be extended up to about 5.12seconds. This change, however, would cause a significant latency gap.

FIG. 11 shows example diagrams 1100 of timing 1110, power consumption1120, and main radio and C-WuRx configurations 1130. Compared to FIG.10, the diagrams 1100 show the results of an improved power-savingsolution employing a C-WuRx to monitor the LTE channel for a wakeupsignal described previously. Instead of keeping a power-hungry LTEreceiver active, it is deactivated and the RRC state information ispreserved. In other words, during the period in which the C-WuRx is on,the LTE receiver is no longer time synchronized with the LTE channel,but the C-WuRx is still able to read the wakeup signal and ignore therest of the complex LTE channel (with its fairly tight synchronizationand highly complex processing demands) so as to consume very littleenergy when reading the wakeup signal.

Furthermore, FIG. 11 shows that the C-WuRx may also be (duty) cycled atshorter periodicity that that of conventional C-DRX, but it still savesenergy compared to the intermitted use of the LTE receiver. For example,when there is data or a message to transmit, the eNB sends a wakeupsignal first to the UE instead of waiting to send the message until thenext DRX active period. And when the wakeup signal arrives, the C-WuRxwakes up the LTE receiver. At that point, since the UE is no longer timesynchronized, the UE spends some additional time, i.e., in a range fromabout 50 ms to about 100 ms, to read the MIB and System InformationBlock1 (SIB1) and obtain timing synchronization that enables the UE toread the PDCCH scheduling the DL packet transmission. The small delay inobtaining timing synchronization does not materially impact the overalllatency and power reduction due to the C-WuRx having a faster dutycycle. For example, based on the timing and power consumption valuesshown in FIGS. 10 and 11, a maximum period of 1.28 s in C-WuRx yields anine-fold energy savings compared to a typical C-DRX implementationhaving a period of 2.56 s.

There are currently two power saving states in LTE: one is DRX duringthe RRC_CONNECTED state and the other is paging during the RRC_IDLEstate. To employ the C-WuRx during the C-DRX state, the UE may want towake up sooner than every 2.56 seconds because the UE is connected andmay desire improved latency. In contrast, if the UE is in the RRC_IDLEstate, it might tolerate more latency delay because it likely does nothave any active applications running. According to some embodiments,therefore, a C-WuRx substitutes for paging and saves about 10 times moreenergy during the RRC_IDLE state. In another embodiment, a C-WuRx canalso be used during a C-DRX state to provide low-power consumption atvery low latency during LWA. These capabilities enable the LTE link tobe readily accessible at low latency, yet also be maintained atextremely low power consumption, similar to as if the LTE link were inan RRC_IDLE state instead of an RRC_CONNECTED state.

The C-WuRx is more preferred over C-DRX in cases where no or limiteddata is being exchanged over the WWAN (e.g., LTE) link. This is sobecause the C-WuRx expects the eNB to send a short wakeup signal beforeit sends a DL packet or messages to the UE. As noted previously, thewakeup signal may occupy 2-6 PRBs. This is not a significant use ofair-interface resources, particularly if the signal is used infrequentlyas in the case when the WWAN link is simply acting as a backup link fordata primarily being sent over the WLAN link (e.g., while data has beenoffloaded to the WLAN). But in cases where WWAN air-interface resourcesare less abundantly available, a UE may optionally elect to employ C-DRXin lieu of C-WuRx techniques.

FIG. 12 shows an example sequence 1200 of the UE 300 and the eNB 212exchange RRC messages to deploy C-WuRx capabilities available on the UE300. For example, the UE 300 and the eNB first negotiate the capabilityof the UE to use the C-WuRx while the UE 300 is connected to a Wi-Fiaccess point 1202 and maintains the WWAN link in the RRC_CONNECTEDstate. The UE 300 signals to the eNB 212 that the UE 300 will expect tobe sent a wakeup signal. Details concerning additional C-WuRx parametersare also exchanged. Examples of parameters specified between the UE andthe eNB for C-WuRx in the RRC_CONNECTED state are as follows.

First, a duty cycle for C-WuRx may be provided. This parameter mayspecify ON and OFF period durations in terms of radio frames, which inLTE last one ms.

Second, an offset, i.e., from a time at which the UE signals that it isshutting down the LTE receiver, is provided to ensure that the UE andthe eNB are aligned in terms of when the C-WuRx starts its duty cycle,especially when multiple UEs within the cell share the same C-WuRxcycle. Similarly, when the UE 300 receives a wakeup signal, an offsettime is provided indicating when the UE's LTE receiver is back inoperation after a predictable period of time (depending on hardwarecircuitry and implementation of C-WuRx functionality on the modem).

Third, a triggering mechanism for deploying the C-WuRx is provided tospecify conditions under which the C-WuRx activates. The trigger mayalso include an inactivity timer value similar to those used for DRX. Insome embodiments, the trigger is a message from the eNB, or it may betriggered in response to elapsed time tracked through a timer. TheC-WuRx active state is not assumed to be entered until its triggercondition for operation during RRC_CONNECTED state, i.e., complete UL/DLdata offload to WLAN, has been achieved and the eNB does not expect anyWLAN measurements at any frequency.

With reference to FIG. 12, after the initial capability exchange todetermine support for LWA capability (not shown), the steps 1210-1270show the steps of establishing the WLAN link and exchange of informationconcerning the use of link for mobile data offloading. The eNB's Wi-Fioffloading decision module may then make a decision to use WLAN link forall of the data traffic transmissions.

To enable the eNB to transmit both data and control messages to the UEusing the WLAN link, the eNB creates Data Radio Bearer Identifiers(DRBIDs) and Signaling Radio Bearer Identifiers (SRBIDs) for both UL andDL. At step 1280, the eNB communicates this information to the UEthrough RRC messages using the LTE control channel link. In addition, ifthe C-WuRx capability was previously negotiated between UE and eNB (asdescribed previously), the eNB sends C-WuRx parameters for theRRC_CONNECTED state in the RRC Connection Reconfiguration message.

At step 1294, the UE's C-WuRx is triggered to turn on and the main LTEreceiver is turned off. This allows the UE to save power otherwiseexpended on the LTE link while still monitoring (with a low-power andlow-latency mechanism) at least a portion of the LTE channel conveyingthe wakeup signal.

Note that, as far as the eNB is concerned, the UE is still inRRC_CONNECTED mode during and following the process of powering down theLTE radio. Thus, the UE need not use additional RRC messages toreestablish its connection with the eNB—it simply wakes up its LTE radioin response to receiving a wakeup signal, obtains synchronization withthe LTE network, and resumes receiving control channel information andother DL messages from the eNB.

Based on the control information from the UE, which may include ameasure of the WLAN link quality, the eNB may elect to once again send1296 a DL message to the UE over the LTE link instead of offloading suchmessages through the WLAN link. To do so, the eNB initially sends awakeup signal to the C-WuRx. Then, the eNB waits a predetermined periodof time, i.e., allowing for the C-WuRx to trigger the powering up of itsLTE radio. Finally, the eNB then sends the DL message in the same mannerit would have sent the DL message as if the UE were in its DRX ONduration period.

In another embodiment, after its LTE radio is ready, the UE may send aScheduling Request message to signal to the eNB that the wakeup wassuccessful, i.e., the UE is available to receive the DL message from theeNB.

VII. Example Embodiments

1. An apparatus of a user equipment (UE) that facilitates reduced powerconsumption during link aggregation of wireless wide area network (WWAN)and wireless local area network (WLAN) links, the UE comprising: a WWANradio to receive through the WWAN link control information from a basestation and, in response to link aggregation, enter a power saving mode(PSM) of the WWAN radio; a WLAN radio to communicate through the WLANlink so as to offload user data transmissions from the base station; anda cellular wakeup receiver (C-WuRx) to receive a wakeup signal providedfrom the base station to wake up the WWAN radio by causing the UE toexit the PSM of the WWAN radio and configure the WWAN radio to resumereceiving the control information from the base station. For example,the control information is the PDCCH scheduling the DL packettransmission that will arrive through the WWAN link.

2. The apparatus of any other example, in which the C-WuRx is configuredto receive the wakeup signal by periodically monitoring at least ofportion of a downlink channel from the base station.

3. The apparatus of any other example, in which the link aggregationcomprises Long Term Evolution (LTE)-WLAN aggregation (LWA).

4. The apparatus of any other example, in which the WWAN radio is a mainLTE radio modem.

5. The apparatus of any other example, in which the WLAN radio is aWi-Fi radio.

6. The apparatus of any other example, in which one or more of the WLANradio, the WWAN radio, or the C-WuRx are integrated in a system on achip (SoC).

7. The apparatus of any other examples, further comprising processingcircuitry to generate a radio resource control (RRC) message forindicating during capability exchange with the base station that the UEincludes the C-WuRx suitable for reduced power consumption.

8. The apparatus of any other example, further comprising: a memorystorage device; and processing circuitry to generate radio resourcecontrol (RRC) state information representing a connected state(RRC_CONNECTED) of the WWAN link for maintaining the RRC stateinformation in the memory storage device during link aggregation.

9. A non-transitory computer-readable storage medium comprisingcontents, which when executed by a computing system, cause the computingsystem to perform operations to: generate signal data to be transmittedthrough a cellular connection with an evolved universal terrestrialradio access network (E-UTRAN) Node B (eNB), the signal data indicatinga user equipment (UE) includes low power wakeup radio (LP WUR); processLP-WUR configuration parameters received from the eNB, the LP WURconfiguration parameters for monitoring a wakeup signal to be receivedby the LP-WUR during mobile data offloading in which user data andcontrol traffic are offloaded from the cellular connection to a wirelessinternet connection provided by a wireless access point; store a stateof the cellular connection and cause a front end module (FEM) of the UEto reduce its power consumption by ceasing reception of a downlinkchannel of the cellular connection in response to the user data andcontrol traffic being offloaded; and in response to the LP-WUR receivingthe wakeup signal from the eNB, restore the state of the cellularconnection and cause the FEM to resume reception of the downlink channelof the cellular connection.

10. The non-transitory computer-readable storage medium of any otherexample, further comprising contents, which when executed by thecomputing system, cause the computing system to perform operations toprocess the LP-WUR configuration parameters including a time intervalparameter by which to configure the LP-WUR to periodically check for thewakeup signal.

11. The non-transitory medium of any other example, in which the UEcomprises a machine-type communications (MTC) device.

12. The non-transitory medium of any other example, in which the UEcomprises a cellular Internet of Things (CIoT) UE.

13. The non-transitory computer-readable storage medium of any of anyother example, further comprising contents, which when executed by thecomputing system, cause the computing system to perform operations to,in response to the FEM receiving the downlink channel of the cellularconnection, process a master information block (MIB) and systeminformation block1 (SIB1) to obtain timing synchronization that enablesthe UE to read a physical downlink control channel (PDCCH) scheduling adownlink packet transmission.

14. The non-transitory computer-readable storage medium of any otherexample, further comprising contents, which when executed by thecomputing system, cause the computing system to perform operations toprocess data radio bearer identifiers (DRBIDs) and signaling radiobearer identifiers (SRBIDs).

15. The non-transitory computer-readable storage medium of any otherexample, further comprising contents, which when executed by thecomputing system, cause the computing system to perform operations togenerate a scheduling request message to signal to the eNB that the FEMis configured to resume reception of the downlink channel.

16. An apparatus for a user equipment (UE), comprising: a first radiofor communicating wirelessly with a base station providing a wirelesswide area network (WWAN); a second radio for mobile data offloading to awireless access point providing a wireless local area network (WLAN);and a cellular wakeup receiver (C-WuRx) configured to receive a wakeupsignal from a base station, the wakeup signal indicating that the C-WuRxshould cause to first radio to transition from a low power consumptionstate during the mobile data offloading to a nominal power consumptionstate for communicating wirelessly with a base station.

17. The apparatus of any other example, in which the wakeup signal ismodulated according to an on-off keying (OOK) tone.

18. The apparatus of any other example, in which the wakeup signal isprovided in a predetermined physical resource block (PRB) location, thepredetermined PRB location to comprise a location within a long termevolution (LTE) frequency band.

19. The apparatus of any other example, in which the wakeup signal isincluded in a narrow frequency band of a downlink channel.

20. The apparatus of any other example, in which the C-WuRx isconfigured to cycle between an active state for receiving the wakeupsignal and a sleep state in which the C-WuRx consumes less power thanthat of the active state and does not receive wireless signals.

21. The apparatus of any other example, in which the C-WuRx isconfigured provide an actuation signal to the first radio in response toreceiving the wakeup signal.

22. A cellular wakeup receiver (C-WuRx) for reducing power consumptionof a wireless wide area network (WWAN) radio of a user equipment (UE),the C-WuRx comprising: receiver circuitry to receive a wakeup signalfrom a base station in response to the UE performing link aggregation bywhich downlink communications from the base station are offloaded to awireless local area network (WLAN); and processing circuitry to:configure the receiver circuitry to periodically monitor at least aportion of a WWAN band for the wakeup signal; and process the wakeupsignal to cause the WWAN radio to resume receiving the downlinkcommunications from the base station.

23. The C-WuRx of any other example, in which the processing circuitryis configured to cycle the receiver circuitry between active and sleepstates.

24. The C-WuRx of any other example, in which the processing circuitryis configured to generate an electrical signal received by the WWANradio that causes the WWAN radio to resume receiving the downlinkcommunications.

25. A method for reducing power consumption in user equipment (UE),comprising: generating signal data to be transmitted through a cellularconnection with an evolved universal terrestrial radio access network(E-UTRAN) Node B (eNB), the signal data indicating the UE includes lowpower wakeup radio (LP WUR); processing LP-WUR configuration parametersreceived from the eNB, the LP WUR configuration parameters formonitoring a wakeup signal to be received by the LP-WUR during mobiledata offloading in which user data and control traffic are offloadedfrom the cellular connection to a wireless internet connection providedby a wireless access point; storing a state of the cellular connectionand cause a front end module (FEM) of the UE to reduce its powerconsumption by ceasing reception of a downlink channel of the cellularconnection in response to the user data and control traffic beingoffloaded; and in response to the LP-WUR receiving the wakeup signalfrom the eNB, restoring the state of the cellular connection andcausinge the FEM to resume reception of the downlink channel of thecellular connection.

26. The method of any other example, further comprising processing theLP-WUR configuration parameters including a time interval parameter bywhich to configure the LP-WUR to periodically check for the wakeupsignal.

27. The method of any other example, in which the UE comprises amachine-type communications (MTC) device.

28. The method of any other example, in which the UE comprises acellular Internet of Things (CIoT) UE.

29. The method of any other example, further comprising, in response tothe FEM receiving the downlink channel of the cellular connection,processing a master information block (MIB) and system informationblock1 (SIB1) to obtain timing synchronization that enables the UE toread a physical downlink control channel (PDCCH) scheduling a downlinkpacket transmission.

30. The method of any other example, further comprising processing dataradio bearer identifiers (DRBIDs) and signaling radio bearer identifiers(SRBIDs).

31. The method of any other example, further comprising generating ascheduling request message to signal to the eNB that the FEM isconfigured to resume reception of the downlink channel.

32. A method, performed by cellular wakeup receiver (C-WuRx), forreducing power consumption of a wireless wide area network (WWAN) radioof a user equipment (UE), the method comprising: receiving thoughreceiver circuitry of the UE a wakeup signal from a base station inresponse to the UE performing link aggregation by which downlinkcommunications from the base station are offloaded to a wireless localarea network (WLAN); configuring the receiver circuitry to periodicallymonitor at least a portion of a WWAN band for the wakeup signal; andprocessing the wakeup signal to cause the WWAN radio to resume receivingthe downlink communications from the base station.

33. The method of any other example, further comprising cycling thereceiver circuitry between active and sleep states.

34. The method of any other example, further comprising generating anelectrical signal received by the WWAN radio that causes the WWAN radioto resume receiving the downlink communications.

35. An apparatus comprising means to perform one or more elements of amethod described in or related to any other example, and/or any othermethod or process described herein.

36. One or more non-transitory (or transitory) computer-readable mediacomprising instructions to cause an electronic device, upon execution ofthe instructions by one or more processors of the electronic device, toperform one or more elements of a method described in or related to anyother example, and/or any other method or process described herein.

37. An apparatus comprising control logic, transmit logic, and/orreceive logic to perform one or more elements of a method described inor related to any other example, and/or any other method or processdescribed herein.

38. A method of communicating in a wireless network as shown anddescribed herein.

39. A system for providing wireless communication as shown and describedherein.

40. A device for providing wireless communication as shown and describedherein.

VIII. Concluding Remarks

Although depicted as a number of disparate functional items, thoseskilled in the art will appreciate that one or more of such elements canwell be combined into single functional elements. Alternatively, certainelements can be split into multiple functional elements. Elements fromone embodiment can be added to another embodiment. For example, ordersof processes described herein can be changed and are not limited to themanner described herein. Moreover, the actions of any flow diagram neednot be implemented in the order shown; nor do all of the actsnecessarily need to be performed. Also, those acts that are notdependent on other acts can be performed in parallel with the otheracts. The scope of the present disclosure, however, is by no meanslimited by these specific examples. Numerous variations, whetherexplicitly given in the specification or not, such as differences instructure, dimension, and use of material, are possible. Skilled personswill understand that many changes may be made to the details of theabove-described embodiments without departing from the underlyingprinciples of the invention. The scope of the present invention should,therefore, be determined only by patent claims.

1. An apparatus of a user equipment (UE) that facilitates reduced powerconsumption during link aggregation of wireless wide area network (WWAN)and wireless local area network (WLAN) links, the UE comprising: a WWANradio to receive through the WWAN link control information from a basestation and, in response to link aggregation, enter a power saving mode(PSM) of the WWAN radio; a WLAN radio to communicate through the WLANlink so as to offload user data transmissions from the base station; anda cellular wakeup receiver (C-WuRx) to receive a wakeup signal providedfrom the base station to wake up the WWAN radio by causing the UE toexit the PSM of the WWAN radio and configure the WWAN radio to resumereceiving the control information from the base station.
 2. Theapparatus of claim 1, in which the C-WuRx is configured to receive thewakeup signal by periodically monitoring at least of portion of adownlink channel from the base station.
 3. The apparatus of claim 1, inwhich the link aggregation comprises Long Term Evolution (LTE)-WLANaggregation (LWA).
 4. The apparatus of claim 3, in which the WWAN radiois a main LTE radio modem.
 5. The apparatus of claim 1, in which theWLAN radio is a Wi-Fi radio.
 6. The apparatus of claim 1, in which oneor more of the WLAN radio, the WWAN radio, or the C-WuRx are integratedin a System On a Chip (SoC).
 7. The apparatus of claim 1, furthercomprising processing circuitry to generate a radio resource control(RRC) message for indicating during capability exchange with the basestation that the UE includes the C-WuRx suitable for reduced powerconsumption.
 8. The apparatus of claim 1, further comprising: a memorystorage device; and processing circuitry to generate RRC stateinformation representing a connected state (RRC_CONNECTED) of the WWANlink for maintaining the RRC state information in the memory storagedevice during link aggregation.
 9. A non-transitory computer-readablestorage medium comprising contents, which when executed by a computingsystem, cause the computing system to perform operations to: generatesignal data to be transmitted through a cellular connection with anevolved universal terrestrial radio access network (E-UTRAN) Node B(eNB), the signal data indicating a user equipment (UE) includeslow-power wakeup radio (LP-WUR); process LP-WUR configuration parametersreceived from the eNB, the LP-WUR configuration parameters formonitoring a wakeup signal to be received by the LP-WUR during mobiledata offloading in which user data and control traffic are offloadedfrom the cellular connection to a wireless Internet connection providedby a wireless access point; store a state of the cellular connection andcause a front end module (FEM) of the UE to reduce its power consumptionby ceasing reception of a downlink channel of the cellular connection inresponse to the user data and control traffic being offloaded; and inresponse to the LP-WUR receiving the wakeup signal from the eNB, restorethe state of the cellular connection and cause the FEM to resumereception of the downlink channel of the cellular connection.
 10. Thenon-transitory computer-readable storage medium of claim 9, furthercomprising contents, which when executed by the computing system causethe computing system to perform operations to process the LP-WURconfiguration parameters including a time interval parameter by which toconfigure the LP-WUR to periodically check for the wakeup signal. 11.The non-transitory computer-readable storage medium of claim 9, in whichthe UE comprises a machine-type communications (MTC) device.
 12. Thenon-transitory computer-readable storage medium of claim 9, in which theUE comprises a cellular Internet of Things (CIoT) UE.
 13. Thenon-transitory computer-readable storage medium of claim 9, furthercomprising contents, which when executed by the computing system causethe computing system to perform operations to, in response to the FEMreceiving the downlink channel of the cellular connection, process amaster information block (MIB) and system information block1 (SIB1) toobtain timing synchronization that enables the UE to read a physicaldownlink control channel (PDCCH) scheduling a downlink packettransmission.
 14. The non-transitory computer-readable storage medium ofclaim 9, further comprising contents, which when executed by thecomputing system cause the computing system to perform operations toprocess data radio bearer identifiers (DRBIDs) and signaling radiobearer identifiers (SRBIDs).
 15. The non-transitory computer-readablestorage medium of claim 9, further comprising contents, which whenexecuted by the computing system cause the computing system to performoperations to generate a scheduling request message to signal to the eNBthat the FEM is configured to resume reception of the downlink channel.16.-21. (canceled)
 22. A cellular wakeup receiver (C-WuRx) for reducingpower consumption of a wireless wide area network (WWAN) radio of a userequipment (UE), the C-WuRx comprising: receiver circuitry to receive awakeup signal from a base station in response to the UE performing linkaggregation by which downlink communications from the base station areoffloaded to a wireless local area network (WLAN); and processingcircuitry to: configure the receiver circuitry to periodically monitorat least a portion of a WWAN band for the wakeup signal; and process thewakeup signal to cause the WWAN radio to resume receiving the downlinkcommunications from the base station.
 23. The C-WuRx of claim 22 inwhich the processing circuitry is configured to cycle the receivercircuitry between active and sleep states.
 24. The C-WuRx of claim 22 inwhich the processing circuitry is configured to generate an electricalsignal received by the WWAN radio that causes the WWAN radio to resumereceiving the downlink communications.
 25. The C-WuRx of claim 22, inwhich the wakeup signal is modulated according to an on-off keying (OOK)tone.
 26. The C-WuRx of claim 22, in which the wakeup signal is providedin a predetermined physical resource block (PRB) location, thepredetermined PRB location to comprise a location within a long termevolution (LTE) frequency band.
 27. The C-WuRx of claim 22, in which thewakeup signal is included in a narrow frequency band of a downlinkchannel.
 28. The C-WuRx of claim 22, in which the C-WuRx is configuredto cycle between an active state for receiving the wakeup signal and asleep state in which the C-WuRx consumes less power than that of theactive state and does not receive wireless signals.
 29. The C-WuRx ofclaim 22, in which the C-WuRx is configured provide an actuation signalto the WWAN radio in response to receiving the wakeup signal.